1. Field of the Invention
The present invention relates to an external output apparatus and method for a portable terminal. More particularly, the present invention relates to an apparatus and method for improving the performance of a determination of whether an earphone is mounted to a portable terminal.
2. Description of the Related Art
The use of portable terminals is now ubiquitous among men and women of all ages, and service providers and terminal manufacturers are competing to develop new and unique products (or services).
For example, portable terminals have now evolved into multimedia devices that provide various functions and services, such as a phone book function, a game function, a Short Message Service (SMS), an Electronic (E)-mail service, a morning call function, a Motion Picture Expert Group (MPEG)-1 or MPEG-2 Audio Layer-3 (MP3) function, a scheduling function, a digital camera function, an Internet service, and the like.
Recently, portable terminals with multimedia player functions, such as a moving picture player function and an MP3 player function, have been launched. Accordingly, users of the portable terminals can play multimedia files by using the portable terminals.
However, using such multimedia functions in public places may cause inconvenience to other people. Accordingly, portable terminals are provided with earphone capabilities in order to prevent such inconvenience.
That is, users of portable terminals can receive music and audio services through earphones coupled to the portable terminals without causing inconvenience to other people and can receive call services through a speaker and a microphone of the earphones even when the users cannot hold the portable terminals to receive the call services.
FIGS. 1A and 1B are diagrams illustrating a process of mounting an earphone in a portable terminal according to the related art.
FIG. 1A is a diagram illustrating an earphone plug and an earphone plug receptacle of a portable terminal according to the related art.
Referring to FIG. 1A, it is assumed that the earphone plug receptacle of the portable terminal supports a 4-pole earphone plug.
The earphone plug receptacle includes a second terminal 101 that is a common ground terminal, a third terminal 102 that is a microphone terminal, a fourth terminal 103 that is a right sound terminal, and a fifth terminal 104 that is a left sound terminal. The second to fifth terminals 101, 102, 103 and 104 contact the corresponding poles of the earphone plug 140. As illustrated in the right side of FIG. 1A, when the earphone plug is not mounted in the earphone plug receptacle, a sixth terminal 105 that serves as a switch terminal of the earphone plug receptacle is connected to the fifth terminal 104 (i.e., the left sound terminal), so that the portable terminal determines that the earphone is not mounted. When the earphone plug 140 is mounted in the earphone plug receptacle, the ground terminal 101, the microphone terminal 102, the right sound terminal 103, and the left sound terminal 104 contact the corresponding poles of the earphone plug 140.
FIG. 1B is a diagram illustrating a state where an earphone plug is mounted/dismounted on/from an earphone plug receptacle of a portable terminal according to the related art.
Referring to FIG. 1B, the fifth terminal 104 (i.e., the left sound terminal) includes a lower portion 104L and an upper portion 104U. Herein, the lower portion 104L and an upper portion 104U may always remain in contact with each other or may only come into contact with each other when the earphone plug 140 is mounted in the earphone plug receptacle. When the earphone plug 140 is mounted in the earphone plug receptacle, the lower portion 104L of the fifth terminal 104 is not in contact with the sixth terminal 105 (i.e., the switching terminal) as shown in the area denoted by 150. Here, when the earphone plug 140 is mounted in the earphone plug receptacle, the lower portion 104L of the fifth terminal 104 may be in contact with the upper portion 104U of the fifth terminal 104.
When the fifth terminal 104 and the sixth terminal 105 are connected to a comparator (not illustrated) and the fifth terminal 104 and the sixth terminal 105 are not in contact as shown in the area denoted by 150, the comparator generates a low signal to recognize that the earphone is mounted.
The left side of FIG. 1B illustrates the state where the earphone plug 140 is not mounted in the earphone plug receptacle and the lower portion 104L of the fifth terminal 104 is in contact the sixth terminal 105.
However, as illustrated in the right side of FIG. 1B, when the earphone plug 140 is mounted in the earphone plug receptacle, the lower portion 104L of the fifth terminal 104 is not in contact with the sixth terminal 105. Here, the lower portion 104L of the fifth terminal 104 may be in contact with the upper portion 104U of the fifth terminal 104.
As illustrated in FIGS. 1A and 1B, the portable terminal determines if the earphone plug is mounted by detecting whether there is contact between the fifth terminal 104 and the sixth terminal 105. However, if foreign substances are caught between the fifth and sixth terminals, the portable terminal determines that the earphone plug is mounted and operates the portable terminal in an earphone mode instead of performing a speaker output operation.
Therefore, a need exists for an apparatus and method for accurately determining when an earphone is mounted to the portable terminal and reducing the unit cost of the portable terminal.